How to verify an email address without sending an email

How to verify an email address without sending an email

How do you keep your email marketing list clean?

One of the most common techniques used by marketers is a simple and self-explanatory one: after every campaign, review the results and take steps to remove unsubscribes, bounces and unengaged contacts. That way, you can ensure the next email you send reaches valid leads only - keeping your list clean and protecting your sender reputation from long-term damage.

However, the problem with this method is that you rely on sending emails as a way to verify email addresses. It works, but it's not terribly efficient - especially if you want to verify emails from a list of brand new leads, or a list that hasn't been worked for a while.

In cases like this, hitting send and waiting for the result won't cut it. If the outcome is a high rate of bounces, spam traps or abuse complaints, this could have a lasting impact on whether your future emails get junked or marked as spam by mail servers that no longer trust you. You could also be blocked from sending an email by your email marketing platform, which can really put a spanner in the works when you have a time-sensitive campaign to run.


Thankfully, it's possible to verify an email address without sending an email. Here's how:

  • Check the email address syntax
  • Check the validity of the email address domain
  • Contact the mail server
  • Check whether the email address exists on a blocklist 
  • Use a trusted email verification tool 

Read on to find out about these methods in more detail. 

About email verification and validation software

Email verification and email validation are two catch-all terms for a family of software tools that verify emails without actually sending an email in the process.

Learn more about why email verification is essential for your business

Generally speaking, these tools will allow marketers to check their email lists in bulk and see which email addresses are valid, which are invalid, and which can't be determined. In doing this before a big campaign, they can identify the invalid emails and remove them from the audience - cleaning their email list and keeping bounces to a minimum.

Most email verification solutions allow users to import their lists manually in the form of a spreadsheet or CSV file, although some also provide API access so you can automate the process from within your marketing automation platform or other business software.

You can check out a free version of our own email verification solution here.

How email verification works

Screenshot showing how Email Hippo's email verification system works

At this point, you may (or may not!) wish to know a little more about how email verification works in practice.

Even if it's the latter, it's worth taking the time to understand the basic principles to avoid potential headaches later down the line.

First of all, you should be aware that email verification is a complex science and no email verification provider can ever claim to be 100% accurate. There's no single magic-wand solution to determine whether an email address is valid or not: rather, there are countless techniques (and new ones being developed all the time) that give us clues and insights we can use to make a judgement.

Some examples of those techniques include:

  • Checking the email address syntax. This is the most basic possible test: does the email address follow the correct format (with an @ sign and a proper domain)?

  • Checking whether the domain in the email address is real and a mail server exists there. It sounds obvious, but anyone who's ever looked at the submissions on a website form will recognise a few instances where an email address follows the correct format but refers to a fake, made-up domain

  • "Pinging" the mail server to check whether an inbox exists at the email address provided, and whether it's set up to accept incoming emails. This sounds complex but basically involves connecting to the mail server and sending some simple messages back and forth to check how it's configured

  • Checking whether the email appears on an existing blocklist or has a past association with spam

These are simple checks that almost every email verification tool will undertake. However, any solution that strives towards a higher level of accuracy will only use this as a starting point and run countless other checks on top of that.

For example, consider the challenges presented by disposable email addresses. A disposable email is an email generated for a single use and for a short period of time. In many cases, disposable emails will pass all of the checks listed above, but are pretty much the last thing you want sitting around in your marketing list.

As such, the most accurate and robust email verification solutions add multiple layers of checks and balances on top of the basic techniques outlined above. They still do this without sending an actual email, though: instead, they assess each email based on a wide range of contextual information from the email address itself, public and proprietary data sources, and trusted third parties.

When you're in the process of choosing an email verification provider, it's worth taking the time to understand as much as you can about their specific technology and the granularity of the results they present back to you. Not every solution is created equal, and this can have a big impact on the accuracy of the results you receive - and, in turn, the success of your campaign.

Get the definitive guide to email verification

We've given you a basic overview here of how to verify an email address without sending an email. As you can see, however, we've only scratched the surface of email verification and how it works.

If you'd like to find out more about this technology, its history and applications, check out our ebook for a definitive guide to email verification.

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Written by: Lisa

Friday, 11 February 2022